Sometimes, it seems, life exists in a series of patterns. Frequently, in the startup founder circle of life, major success is born out of failure.

Image: Talia Herman/Slack

If a founder is lucky, he or she might strike gold like that one time. However, in rare instances an individual or team can turn a misstep or redirection into something that disrupts and industry and changes the way users see the space.

Cal Henderson, CTO of the popular message app company Slack, is one of the founding members of a team that has managed to turn a side project into a business twice. It began in 2003 when he started working with Stewart Butterfield, Eric Costello, and Serguei Mourachov. Henderson was working on the photo-sharing site Flickr as a side project to fund the development of a web-based game called Game Neverending.

"I really wanted to work on the game, but they had really no money to fund the development of the game," Henderson said.

So, he joined the team to work on Flickr while the rest of the team worked on the game, with the idea being that he would eventually be able to work on the game. Flickr exploded in popularity and focus shifted to the photo-sharing site. In 2005, they sold Flickr to Yahoo and moved down to San Francisco to work for Yahoo.

Four years later, they all left Yahoo and started another company to try and once again build a game. The game failed, but out of that failure came Slack. The tool was developed to improve internal communications among the team members working on the game, and it worked so well for them that they decided to build a business around it.

The company exploded in popularity, spreading mostly by word-of-mouth. The tool has hundreds of thousands of active daily users and just received a more than billion dollar valuation earlier this year.

It's not exactly commonplace for the same team to grow a company like that twice with the same people.

It's interesting that Henderson and the Slack team built a successful enterprise app, because their background is predominantly in the consumer web. However, that does make them an archetypal case study on consumerization in the enterprise.

In the past, there were fewer choices in enterprise software and the quality was poor, Henderson said. It also used to be very expensive to develop software, so it was less of a competition in quality, and more about who could sell.

"If you look at business tools from 10 years ago, they're terrible in terms of using them because you weren't selling them to individual users," Henderson said.

Everybody who uses software at work now has a smartphone or tablet, so that sets the bar for how they expect to experience software tools at work. And, it shouldn't come as a surprise that the tool Henderson relies on the most to get stuff done is Slack itself.

In terms of number of messages per user per day, the Slack team is actually the biggest users of the tool. They're not the biggest team using it by any means, but they use it at a very high volume. Additionally, Henderson said they use AWS to host Slack, and they rely on Google Docs, ZenDesk, and other internal tools they have built.

When approaching the product, Henderson said he is focused on quality, but it's more important to ship.

"A strong core philosophy is that we should finish things to a reasonable extent, then get them out there," he said. "That's always an internal struggle between perfection and shipping things on time or shipping things quickly."

As part of a company that has experienced a high valuation, Henderson said that there is a lot of money available to startups, and it is a good time to start a company, but it doesn't guarantee success. But, he said, the lower cost of building a company combined with the resources available means the barriers to entry are lower.

"We'll see more and more people starting things, and most of them will fail," Henderson said. "But, we're going to see a ton more interesting new stuff that we wouldn't have seen five years ago."

In his own words...

What do you do to unplug?

"I have a seven-month-old son now. My wife and I had a baby last year, so that's been a very big shift for us in terms of what we do when we're not working. So, mostly spend time with my son, but that's a fairly recent development. More historically, I try and read a lot. For the last 15 years, I've tried to read a book a week, and I've mostly managed. I read a ton. It's tough to keep that going with both Slack and a baby.

"In 2006, I wrote a book about engineering web apps — it was largely about Flickr. What was interesting there was that back in 2006 there weren't smartphones and I was doing a daily commute down to the Valley to work at Yahoo. So, I would have an hour of uninterrupted offline time in which I could write, which doesn't exist anymore. So, I'm not sure that I'd ever be able to write another book, because I'm always online and always available.

What's the best thing you've read lately?

"Mostly, I read terrible science fiction, so that isn't generally very useful. In terms of things that are useful to read I've been reading, and I constantly try to read, Facebook's engineering blog. Looking at the things that they've had to deal with as they've grown as an organization is really interesting.

"One of the big shifts, going back a bit, between Web 1.0 and Web 2.0, was that in the first round of the dot-com boom, everybody thought that how they built software and how software was put together was secret sauce. In Web 2.0, a lot more things were built on open source, and there was a lot more was shared about how to go about the technical infrastructure of building things. I think something that Facebook is championing is talking about the process of engineering something with a lot of people, which is otherwise pretty secretive. They've been writing a lot of interesting stuff about how they scale up their operations to have thousands of developers working on the same bit of software, and that's really interesting."

If you weren't working in tech, what other profession would you love to try?

"It's really hard to image at this point, but when I was a teenager my other interest was physics. So, I was like 'maybe I should be a physicist or maybe I should get into computer science.' It's kind of hard to imagine not doing what I do now, but maybe that would be it. Nothing else has ever really caught my imagination. I probably wanted to be a fighter pilot when I was five years old, but I'm colorblind, so that's out of the question."